Communication devices, such as portable radios and cellular phones, often incorporate an antenna assembly with an extendible portion. In such devices, an antenna element is extended for higher antenna gain when the communication device is in use. The antenna element is retracted when no longer needed to present a more compact package. A typical prior art example of this type of antenna assembly can be found in U.S. Pat. No. 4,868,576 issued to Johnson, Jr., entitled Extendable Antenna For Portable Cellular Telephones With Ground Radiator. Another example is found in U.S. Pat. No. 5,343,213, issued to Kottke, et al., on Aug. 30, 1994, for a Snap-In Antenna Assembly, which is hereby incorporated by reference.
The prior art teaches a variety of ways to attach an extendible antenna to a communication device. There are many factors involved in choosing an attachment approach, including considerations for space consumption, aesthetics, durability, and facility for assembly and disassembly. One approach that is widely practiced has a slidable antenna element mounted within a threaded sleeve that is secured to a portion of the housing for a communication device. An example of this approach is described in U.S. Pat. No. 5,079,558, issued to Koike on Jan. 7, 1992 for an Extendable Antenna Device, which is hereby incorporated by reference. In the Koike patent, a threaded sleeve encases an extendible antenna element. The threaded sleeve includes a protruding head portion that provides a gripping surface for screwing the threaded sleeve within a corresponding threaded retainer attached to a communication device. The protruding head presumably supports the assembly and disassembly of the extendible antenna. For modern compact communication devices, such protruding head may be considered to be space consuming and not aesthetically appealing. Moreover, notwithstanding a variety of available designs, it would be expected that this threaded insert approach for attaching an extendible antenna would require the use of cumbersome and potentially expensive tools.
Communication devices having an extendible antenna attached by a threaded sleeve have been found to have satisfactory performance. However, these type of antenna assemblies typically require a tool for assembly and disassembly. The requirement of special tools for installation of an extendible antenna creates manufacturing difficulties and limits the ability to offer a user install option. Therefore, it is desirable to have an extendible antenna assembly that facilitates installation.